Stephen Breyer, who clerked for Justice Arthur Goldberg in the Supreme Court's 1964 term, is the fifth former Supreme Court law clerk to join the Court as a Justice, a company that includes Byron White, William Rehnquist, John Paul Stevens, and John Roberts. This article explores the influence of his clerkship on Breyer's work as Justice. Although Goldberg, a self-proclaimed judicial activist, became the reliable fifth vote for the Warren Court majority and Breyer is known as a member of his Court's liberal bloc, their relationship is more complex than that obvious link. Breyer and Goldberg share similar urban Jewish backgrounds, a commitment to protection of individual rights, an appreciation of the usefulness of foreign law to their jurisprudence, a nuanced approach to the Establishment Clause, and an ability to maintain civility while disagreeing with their colleagues. They diverge, however, in significant respects in their interpretation of the judicial role. Goldberg was a candid supporter of the Warren Court's liberal agenda and remained, during his brief tenure, a predictable vote. In contrast, Breyer brings to the Court a pragmatic approach that relies heavily on empirical data and takes each case on its own merits, making him capable of casting surprising votes. Despite these differences, there is a subtler bond between Breyer and Goldberg in their judicial temperaments, a shared tendency - one that Breyer traces back in part to advice from Goldberg - to seek common ground with opponents as well as allies, to avoid harsh critiques that alienate colleagues, and to consider fairly the other side's position while working persistently to make one's own prevail.